Polynitro-substituted dibasic acids and esters



United States Patent Ofiice 3,000,932 Patented Sept. 19, 1961 3,000,932 POLYNITRO-SUBSTITUTED DIBASIC ACIDS AND ESTERS Karl Klager, Pasadena, Calif., assignor to Aeroget-General Corporation, Azusa, Oalifi, a corporation Ohio No Drawing. Filed Jan. 28, 1957, Ser. No. 636,839 20 Claims. (Cl. 260-485) This invention relates to new compositions of matter, and in particular, to polynitro-substituted dibasic acids and esters thereof having the general formula:

(R N02 N02 1}10: (i!) n0- 'ACHz-OCH|CA-OOR N 03 NO: wherein R is a lower alkyl or hydrogen radical, A is a lower alkylene radical and X is a hydrogen or nitro radical.

This application is a continuation-in-part of my copending application Serial No. 392,479, filed November 16, 1953, and now abandoned, and my copending application Serial No. 337,211, filed February 16,1953 now abandoned.

The new compositions of my invention are prepared by condensing esters of nitroallyl alcohol with mes-dinitroalkanoic acid esters, in accordance with the general reaction scheme set forth below:

wherein R is a hydrogen or organic radical, preferably alkyl, Y is an organic radical, preferably alkyl, M is an ion of an alkali or alkaline earth metal, A is a lower alkylene radical and R is an alkyl radical.

In place of the ester of nitroallyl alcohol, a diester of 2-nitro-1,3-propanediol can be used, as for example, 2 nitro-1,3-diacetoxypropane. It is believed that the diester generates the nitroallyl alcohol ester in situ and then reacts in the manner illustrated above.

- Since the acid portion of the nitroallyl ester does not enter into or affect the reaction, Y can be any organic radical including phenyl, benzyl, heterocyclic, aliphatic, cycloaliphatic, or the like, without departing from the scope of my invention. Similarly, when a diester of 2- nitro-1,3-propanediol is used as the starting material, the acid portion can be any organic acid inasmuch as this portion of the diester does not enter into or affect the reaction in any way.

- R, the alcohol portion of the dinitroalkanoic acid ester, can also be any organic radical. Although alkyl is preferred, R can be aromatic, cycloaliphatic, heterocyclic, substituted aliphatic, or the like, without departing from the scope of my invention. Likewise, the dibasic acids and diacid halides of my invention will react with any organic alcohol to form esters in the usual manner.

When R in the composition I is alkyl, the corresponding dibasic acid is prepared by hydrolysis with a strong mineral acid in the conventional manner. The reaction of compound I with nitric acid produces the hexanitro derivative and at the same time hydrolyzes the ester when R is alkyl. Composition II can be converted to the corresponding hexanitro dibasic acid ester by direct esterification with an alcohol, however, it is preferred to first convert the dibasic acid to its corresponding diacid halide, in the conventional manner, as for example, by reaction with phosphorous pentachloride and phosphorous-oxy chloride prior to esterification.

The new compositions of my invention are valuable explosives and can be used in any conventional explosive missile, projectile, rocket, or the like, as the main explosive charge. An example of such a missile is disclosed in United States Patent No. 2,470,162, issued May 17, 1949. One way of using the high explosives of this invention in a device such as that disclosed in United States Patent No. 2,470,162, is to pack the crystalline explosive in powder form into the warhead of the missile. Alternatively, the crystals can be first pelletized and then packed. A charge thus prepared is sufficiently insensitive to withstand the shock entailed in the ejection of a shell from a gun barrel or from a rocket launching tube under the pressure developed from ignition of a propellant charge, and can be caused to explode on operation of an impactor time fuse-mechanism firing a detonating explosive such as lead azide or mercury fulminate.

The dibasic acids of my invention can also be converted to their corresponding diisocyanate compounds by reacting their corresponding diacid halides with sodium azide followed by hydrolysis to yield the desired diisocyanate as disclosed in assignees copending patent application Serial No. 574,035, filed March 26, 1956. The diisocyanate compounds thus obtained react with nitrodiols such as 2,2,4,4-tetranitro-1,5-pentanediol to form nitro-substituted polyurethanes, as disclosed in assignees copending patent application Serial No. 422,649, filed April 12, 1954, now abandoned.

The nitro-substituted polyurethanes thus obtained can be used as a primary propulsion source in rocket-propelled vehicles, and can also be used as a propellant for artillery missiles. When used as the primary propulsion source for rocket vehicles, they can be conveniently ignited by a conventional igniter, as for example the igniter disclosed in assignees copending patent application Serial No. 306,030, filed August 23, 1952. The propellant is preferably cast in tubular form and restricted in the conventional manner with a relatively inert resin, such as a non-nitrated polyurethane foam or a polyester resin, and placed inside a chamber having one end open and leading into a conventional venturi rocket nozzle. Upon ignition, large quantities of gases are produced and exhausted through the nozzle creating propulsive force.

The following examples are provided to more clearly. illustrate my invention and are not intended to limit or define the scope of my invention in any way:

EXAMPLE I Preparation of 4,4,6,6,8,8-hexanitro-1,1I- undecarlea'ioic acid ants were mixed the temperature was kept for three additional hours at 45-50 C. A yellow insoluble oil was separated during the reaction. The mixture was cooled to room temperature and the upper water layer decanted. The residue was washed once with water and dissolved in l000 ml. 70% nitric acid. The mixture warmed up spontaneously and was heated to 50 C. with stirring. At this temperature N development began and the temperature rose rapidly to 70 80 C. Copious brown fumes were evolved. When the reaction subsided and the temperature dropped below 50 C., the mixture began to crystallize. The crystallization was completed at l0-15 C. and the crystals were collected in a sintered-glass funnel. After being washed with ice water, the white crystals were dried in a desiccator. The yield varied between 100 and 140 gm. The melting point depended on the relative proportions of acids in the mixture and was generally between 135-155 C. with decomposition. Several fractional crystallizations from nitric acid accompanied by some loss of material finally gave a pure fraction, M.P. 154-l55 C. The mixed melting-point with 4,4,6,8,S-pentanitro-undecanedioic acid showed depression (M.P. 138-142 C.).

Analysis-Calculated for C H N O Percent C, 21.17; percent H, 2.90; percent N, 17.29. Found: Percent C, 26.52; percent H, 2.91; percent N, 16.80.

Heat of combustion calculated: 2556 cal./ gm. Found: 2541 cal./gm.

If in the above example some strong mineral acid such as hydrochloric, phosphoric, etc., is used in place of nitric acid for hydrolysis, 4,4,6,8,8-pentanitro-l,ll-undecauedioic acid is obtained.

EXAMPLE II Preparation of 4,4.6,6,8,8-hexanitro-1,1 1- undecanedioyl chloride A mixture of 14 gm. 4,4,6,6,8,S-hexanitro-undecanedioic acid and 40 ml. phosphorous-oxy chloride was allowed to react gradually with 19 gm. phosphorous pentachloride. The temperature rose to 55 C.; the mixture was then heated to 80 C. for minutes. The phosphorousoxy chloride was removed from the solution under vae uum until crystals appeared, and 30 ml. benzene was added to complete crystallization. The crystals were collected and washed with hexane and absolute ether. The yield was 8.4 gm. Hexane caused precipitation of a second fraction, which was filtered oft and washed with 4.6 gm. of absolute ether. The total yield was 13.0

A sample recrystallized from phOSPhOl'OUS-OXY chloride and monochlorobenzene melted at 120-121 C.; this sample was used for analysis. The mixed meltingpoint with 4,4,6,8,8-pentanitro-undecanedioyl chloride (M.P. 141 C.) was depressed to 110-ll2 C.

Analysis.-Calculated for CnHnNgOnCigl Percent C, 25.25; percent H, 2.31; percent N, 16.07; percent Cl, 13.55. Found: Percent C, 25.85; percent H, 2.49; percent N, 15.96; percent Cl, 13.25.

EXAMPLE III Preparation of dimethyl 4,4,6,6,8,8-hexanitro- 1 ,1 1 -undecanedioate (a) A three-necked flask provided with -a. stirrer. thermometer and reflux condenser was charged with 2 gm. 4,4,6,6,8,S-hexanitro-undecanedioyl chloride, 15 ml. methanol and 2 ml. conc. sulfuric acid. The solution was refluxed for 45 minutes, then diluted with methylene chloride. The methylene chloride solution was washed with water, with dilute sodium bicarbonate solution, and again with water. After being dried over sodium sulfate, the solvent was evaporated and 1.8 gm. of a viscous oil was obtained. When treated with absolute ether the oil was converted into crystals; these were collected and recrystallized from a concentrated methylene chloride so lution by the addition of absolute ether. The melting point was 74 C. and the mixed melting point with di- 4 methyl 4,4,6,8,8-pentanitro-undecanedioate (M.P. 62- 63 C.) was 45-52 C.

(b) Another preparation was run with 2 gm. 4,4,6,6, 8,S-hexanitro-undecanedioyl chloride as prepared under Example 11. The sample was dissolved in 10 ml. absolute methanol. After 30 minutes refluxing methylene chloride was added. The methylene chloride solution was washed with water three times, dried over sodium sulfate and evaporated. The crystals obtained by treating the residue with absolute ether melted at 74 C. and were identical with the compound prepared above.

Anaiysis.-Calculated for CmHmNqOmZ Percent C, 30.36; percent H, 3.53; percent N, 16.34; percent 0011,, 12.07. Found: Percent C, 30.90; percent H, 3.58; percent N, 16.28; percent OCH 11.68.

EXAMPLE IV Preparation of 4,4,6,8,8-pentanitro- 1 ,1 1 -undecanediaic acid A three-necked flask with stirrer, thermometer and dropping tunnel was charged with a solution of 171 gm. of the sodium salt of methyl 4,4-dinitrobutyrate in 500 ml. of water. A mixture of 60 gm. of nitroallyl acetate, 50 ml. methanol and 24 gm. of acetic acid was dropped into the flask over a period oi 30 minutes while maintaining the temperature of the flask at 20-25 C. Stirring was continued for three hours between 40-45 C. and the mixture allowed to stand overnight. After standing, the mixture was diluted with methylene chloride and the methylene chloride solution was extracted several times with water. The residue (174 gm.) of crude dimethyl 4,4,6,8,8-pentanitro-1,1l-undecanedioate was heated with 1750 ml. of 1 to 1 HQ on a steam bath while the mixture was stirred. Stirring was continued for six hours and after cooling, crystals were obtained which were filtered and washed with water. The crystals were found to decompose at C. The crystals were then recrystallized from ether and methylene chloride and a 25% yield of theoretical 4,4,6,8,8-pentanitro-l,1l-undecanedioic acid was obtained.

Both higher and lower homologucs of the compounds of my invention can be prepared simply by reacting appropriate starting materials in accordance with the teachings of my invention. For example, 5,5,7,7,9,9-hexanitro-1,13-tridecanedioic acid is prepared by reacting nitroallyl acetate or methyl 4,4-dinitrobutyrate with methyl 5,5-dinitropentanoate followed by nitration and hydrolysis with nitric acid; diethyl 4,4,6,6,8,8-hexanitro-1,11- undecanedioate is prepared by reacting ethyl alcohol with 4,4,6,6,8,S-hexanitro-undecanedioyl chloride (prepared in Example 11); and dimethyl 5,5,7,9,9-pentanitro-tridecanedioate is prepared by reacting nitroallyl acetate or Z-nitro- 1, -diacetoxypropane with methyl 5,5-dinitropentanoate.

It is preferred to use the w,w-dinitroalkanoate in the form of its alkali or alkaline earth metal salt such as sodium potassium, calcium, magnesium, etc. Under reaction conditions, it is believed that the salt breaks down to yield the free compound which then reacts to form the desired product. However, in any event, the product is obtained whether the initial material is the free compound or the salt.

The reaction forming the pentanitro derivative is catalyzed by alkali and alkaline earth metal ions. When a metal salt of the dinitro ester is used as the starting material, degradation of the salt to the free ester provides'sufficient metal ions to catalyze the reaction. When the ester is not used in the form of the salt, it is necessary toadd a' small'amount, usually on the order of about 1% by weight of an alkali or alkaline earth metal salt, to catalyze the reaction.

The reaction temperatures used in the present invention are not critical and can be varied as desired. It will be appreciated, however, that at higher temperatures the reaction is more difficult to control, while at lower temperatures the rate is considerably slower.

Methyl 4,4-dinitrobutyrate used as the starting material iii the practice of my invention is prepared by the method disclosed in my copending patent application Serial No. 330,597, filed January 9, 1953, now US. Patent No. 2,668,176. Nitroallyl acetate is prepared by the method disclosed in assignees copending patent application Serial No. 445,885, filed July 26, 1954, now abandoned. 2- Nitro-l,3,-diacetoxypropane is prepared by esterifying 2-nitro-L3-propanediol with acetic anhydride or acetyl chloride.

1 claim:

1. As compositions of matter, the polynitro compounds having the formula:

wherein R is a radical selected from the group consisting of hydrogen and lower alkyl radicals, A is a lower alkylene radical and X is a radical selected from the group consisting of hydrogen and nitro radicals.

2. As a composition of matter, 4,4,6,6,8,8-hexanitro- 1,1l-undecanedioic acid having the structural formula:

3. As a composition of matter, S,5,7,7,9,9-hcxanitro- 1,13-tridecanedioic acid having the structural formula:

N: N0, N0:

4. As a composition of matter, 4,4,6,8,8-pentanitro- 1,1l-undecanedicic acid having the structural formula:

5. As a composition of matter, dimethyl 4,4,6,6,8,8- hexanitro-Lll-undecanedioate having the structural 6. As a composition of matter, diethyl 4,4,6,6,8,8- hexanitro-Ll l-undecanedioate having the structural formula:

7. As a composition of matter, dimethyl 4,4,6,8,8-

'6 9. The method of preparing the polynitroconipoitnds having the formula:

NO: NOI N0! ao-ii-a-d-orn- -0Hr- Ar l0R rco, l qos which comprises reacting an ester having the formula:

N0: 0 Ht J-A-HIOR IJO:

with an ester selected from the group consisting of esters of nitroallyl acetate and diesters of 2-nitro-1,3-propane diol in the presence of an alkali or alkaline earth metal ion, wherein R is a radical selected from the group consisting of hydro-gen and lower alkyl radicals, A is a lower alkylene radical, and X is a radical selected from the group consisting of hydrogen and nitro radicals.

10. The method of claim 9 wherein the said ion is provided and said dinitro ester is generated in situ from a salt of said dinitro ester selected from the group consisting of the alkali and alkaline earth metal salts thereof.

11. The method of preparing the polynitro compounds having the formula:

which comprises reacting a dinitro ester having the formula:

medium NI-OI with an ester selected from the group consisting of esters of nitroallyl acetate and diesters of 2-nitro-l,3-propanediol in the presence of an ion selected from the group consisting of the alkali and alkaline earth metal ions, wherein R is a radical selected from the group consisting of hydrogen and lower alkyl radicals and A is a lower alkylene radical.

12. The method of preparing the polynitro compounds having the formula:

which comprises nitrating a polynitro compound having the formula:

with nitric acid, wherein A is a lower alkylene radical and R is an organic radical.

13. The method of preparing polynitro compounds having the formula:

which comprises hydrolyzing a polynitro compound having the formula:

with a strong mineral acid, wherein R is an organic radical and A is a lower alkylene radical.

14. The method of preparing 4,4,6,6,8,8-hexanitro-l, ll-undecanedioic acid which comprises reacting a di-lower alkyl ester of 4,4,6,8,8-pentanitro-l,1l-undecanedioic acid with nitric acid.

is. re: m thod o JJJSJ-heXmi rol3-tridecanedioic acid which comprises reacting a cli lower alkyl ester 91'' 5,5,7 ,9,9-pentanitro-l,13-tridecanedioic acid with nitric acid.

16. The method of preparing 4,4,6,8,8-pentanitro-l,l1- undecanedioic acid which comprises hydrolyzing a dilowg elkyl este oi ,.6, .8-pes1anitro-1 l-undecanedioic acid with a strong mineral acid selected from the group consisting of sulfuric acid, hydrochloric acid, hydrobrornic acid, phosphoric acid, trifluoroncetic acid. and mixtures thereof.

1?. The method of preparing dimethyl 4,4,6,6,8,8-hexanitm-Lll-undeeanedioate which comprises reacting a 4,4,6,6,8,8-hexanitro-l,ll-undecanedioyl halide with methyl alcohol.

18. The method at prepa ins diethyl 4.456534% nitrodJl-undecanedioate which comprises reacting l :i4,%6i8.8-hexanitro-1,1l-undecauedioyl halide with ethyl- 19. The method of preparing dimetlryl 4,4,63,8-pentanitro-Lll uudeeanedioate which comprises reacting a salt selected from the group consisting of the alkali nd alkaline earth metal salts of methyl 4,4-dinitmbutyrate with Z-nitro-1,3-diacetoxypropane.

20. The method of preparing dimethyl 5,5,7,9,9-pentanitro-LB-tridecanedioate which comprises reacting methyl 5,5-dinitropentanoate and nitroallyl acetate in the presence of an ion selected from the group consisting of the alkali and alkaline earth metal ions.

No references cited. 

1. AS COMPOSITIONS OF MATTER, THE POLYNITRO COMPOUNDS HAVING THE FORMULA:
 9. THE METHOD OF PREPARING THE POLYNITRO COMPOUNDS HAVING THE FORMULA: 